São João de Meriti weather by month: averages, rainfall & climate trends
Warmth in São João de Meriti is remarkably steady: only 6.5°C separates the warmest month from the coolest, so there is no cold season to speak of. Rainfall leans toward the stretch from November to March. São João de Meriti weather by month: average temperatures, rainfall, extremes and how the climate has changed since 1940.
Today vs average
−1.4°Chigh near average
How it's changed
+1.4°Caverage temperature, 2016–2025 vs 1940–1949average temperature vs 1940–49163days above 30°C a year now (2016–2025) · 99 in the 1940sdays above 30°C · 99 in the 1940s+1.4°C vs the 1940s · see how it's changed →Weather by montha typical year, averaged over the full recordJanuary, rain 272 mmhigh 31°low 24°February, rain 217 mmhigh 32°low 24°March, rain 227 mmhigh 30°low 23°April, rain 131 mmhigh 29°low 21°May, rain 80 mmhigh 27°low 19°June, rain 54 mmhigh 26°low 17°July, rain 50 mmhigh 26°low 17°August, rain 55 mmhigh 27°low 17°September, rain 90 mmhigh 27°low 19°October, rain 141 mmhigh 28°low 20°November, rain 213 mmhigh 29°low 21°December, rain 269 mmhigh 30°low 23°wettest month January, 272 mm · 1,800 mm a yearsee month by month →Right now
What it's doing today vs the historical average for this date.Right now
21.0°
On this date: October 19
High near average · −1.4°C
- Highest since 1940: 37.3° · 2014
- Lowest since 1940: 15.7° · 1948
- One year ago: 23° / 18°
Every October 19 in history, coldest to hottest
Dots show daily highs (top) and lows (bottom) for each October 19 on record (n = 87). Outlined dots are today's forecast.
Area we sample
Each city's history comes from one ERA5 grid cell, about 28 km across, shown by the dashed box. Near mountains or coasts, conditions can vary across the cell.
Location & data
Historical weather for São João de Meriti is sampled from the ECMWF ERA5 reanalysis at 22.80°S, 43.37°W, with daily records since 1940.
- Coordinates
- 22.80°S, 43.37°W
- Time zone
- America/Sao Paulo
- Period
- 1940–2026
- Data source
- ERA5 (ECMWF)
Last 30 days
23 of the last 31 days were warmer than the historical average for that date. Average difference: +1.4°C.
Each bar is one day, from morning low to afternoon high. Warm-colored bars are days whose mean ran above average; cool bars ran below. The dot inside the bar is the daily mean. The shaded band is the typical 10–90% range expected for that date. Average = the day's mean temperature averaged across every year of record (1940–2026) for that calendar date.
This date over the years
One dot per year, showing the mean temperature on this calendar date. Dots are warmer or cooler than the long-term average (dashed line); the shaded band is the typical 10–90% range, and the highlighted dot is today's forecast. Based on ERA5 reanalysis: modelled estimates, not station readings.
Weather by month
Average temperatures and rainfall for each month: a typical year, from the full record.Climate overview
February brings the year's peak warmth, with afternoons typically reaching 31.7°C and nights around 23.6°C. At the other extreme, July brings afternoon highs of about 25.6°C and typical overnight lows of 16.7°C.
The yearly total for São João de Meriti comes to about 1,800 mm; monthly amounts range from 50 mm in July up to 272 mm in January.
The record here starts in 1940, and since then the annual mean in São João de Meriti has climbed 1.4°C from the first ten years to the last ten. Days above 30°C have grown noticeably more frequent, from around 100 a year in the first decade to about 165 in the last.
Climate graph (climograph)
February is the warmest month, July the coolest: a yearly swing of 7°C. Wettest month: January (~272 mm). Whole year averages ~1,800 mm of rain.
Bars = average monthly rainfall (right axis). Lines = average daily high and low (left axis). Average = each month's value averaged across every year of record (1940–2026).
Monthly wind
Average daily peak wind at 10 m, by month.
Monthly solar energy
Average daily incoming solar energy in megajoules per square metre: the record's own proxy for how sunny the month is.
São João de Meriti month by month: what to expect
Typical conditions for each month, averaged across the full record (since 1940). Daylight is the time from sunrise to sunset. Highest and Lowest are the most extreme values in the ERA5 dataset (modelled since 1940), so they can differ from official weather-station readings.
| Month | Avg high | Avg low | Rain | Daylight | Highest | Lowest |
|---|---|---|---|---|---|---|
| January | 31.3° | 23.5° | 272 mm | 13.3 h | 39.7° (1995) | 18.0° (1945) |
| February | 31.7° | 23.6° | 217 mm | 12.8 h | 39.2° (2010) | 18.5° (1968) |
| March | 30.4° | 22.9° | 227 mm | 12.2 h | 38.3° (2010) | 17.0° (1979) |
| April | 28.5° | 21.1° | 131 mm | 11.5 h | 36.7° (2019) | 13.3° (2014) |
| May | 26.7° | 18.8° | 80 mm | 10.9 h | 36.8° (2024) | 11.7° (2020) |
| June | 25.9° | 17.4° | 54 mm | 10.6 h | 33.9° (1997) | 8.9° (1979) |
| July | 25.6° | 16.7° | 50 mm | 10.7 h | 36.9° (2023) | 8.6° (2000) |
| August | 26.7° | 17.4° | 55 mm | 11.2 h | 38.5° (2023) | 10.2° (1947) |
| September | 27.4° | 18.8° | 90 mm | 11.9 h | 41.3° (1961) | 11.0° (2011) |
| October | 28.1° | 20.4° | 141 mm | 12.5 h | 39.8° (2020) | 13.5° (1950) |
| November | 28.6° | 21.3° | 213 mm | 13.1 h | 41.5° (2023) | 13.6° (1956) |
| December | 29.9° | 22.6° | 269 mm | 13.4 h | 39.2° (2015) | 15.9° (1963) |
How it's changed
Year-by-year signals from 1940 to today.Climate stripes
Annual mean shifted from 1940–1949 to 2016–2025 by +1.4°C.
Each vertical stripe is one year. Color encodes how much that year's annual mean differed from the long-term average. Average = each year's annual mean compared to the average of all years (1940–2026). cooler ← → warmer
Annual mean temperature
Long-term trend: +0.20°C per decade.
One point per year, showing the temperature averaged across the whole year. The dashed line is the least-squares long-term trend. Based on ERA5 reanalysis: modelled estimates, not station readings.
Seasonal warming
Mar–May is warming fastest: +0.23°C per decade.
Each faint line is one three-month period's average per year; the bold dashed line is its long-term trend. Different parts of the year often warm at different rates. Based on ERA5 reanalysis: modelled estimates, not station readings.
Hot days vs frost days
Days ≥ 30°C per year: 99.4 early in the record → 162.8 recently. Frost days: 0 → 0.
Thin lines are raw yearly counts; thick lines are the smoothed trend that removes year-to-year noise. The hot-day threshold is auto-picked per city so the line actually moves. Average = a centered 5-year rolling average to smooth weather noise.
Yearly hot & cold extremes
Hottest day since 1940 in 2023, coldest in 2000: 41.5°C / 8.6°C.
One point per year: the single hottest and coldest day recorded that year.
Annual rainfall
~1,800 mm/year on average. Last decade: −13% vs that average. Long-term trend: −48 mm per decade.
One bar per year of total rainfall. Dashed line is the long-term average. Average = the average annual rainfall across every year of record (1940–2026).
Day-by-day grid
Each tiny square is one calendar day across the full record, about 30,000 days per city. Use the mode switch above the chart: Anomaly colors each day by how far it ran from the historical average for that date (red = warmer, blue = cooler), Daily mean temp shows the absolute mean temperature for the day (useful to see seasons and heatwaves), and Precipitation shows daily rainfall (useful to spot wet/dry seasons and droughts). Average = the long-term average for that calendar date (1940–2026).
Frequently asked questions about São João de Meriti
Which is the warmest month in São João de Meriti?
How does today's temperature in São João de Meriti compare to the historical average?
How much has São João de Meriti warmed since 1940?
How much does it rain in São João de Meriti?
What is the average temperature in São João de Meriti?
What are the average temperatures in São João de Meriti by month?
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